A MIMO system achieves diversity increasing transmission rate by that a transmitter transmits different information through plural antennas using the same carrier wave, and a receiver separates and composes signals.
A channel capacity of a MIMO system is restricted by the number of antennas of a receiving side (when it is less than the number of antennas of a sending side), and when the number of antennas is Nr, channel capacity becomes only Nr times at most.
A fractional sampling is proposed as a method for increasing the number of antennas equivalently.
A fractional sampling system attains diversity with G antennas equivalently using a sampling G times faster than a sampling speed required in a conventional OFDM demodulation (“G” is a positive integer.).
By this structure, it is possible to increase a channel capacity of a MIMO system.